The invention relates to an apparatus for compacting empty plastic bottles, comprising a housing or frame, means for fixing the bottle, means for heating a part of the bottle and a press unit for compacting the softened bottle.
It is known that beverages and other food products are filled more and more often into plastic bottles for sale, and the manufacturers want to produce rather one-way bottles rather than repurchasable ones. Thus, these bottles are found in large amounts in waste yards or in nature, contaminating thereby the environment or increasing to a great extent the amount of waste.
A further problem is caused by the fact that the material of the plastics do not decompose, thus the damage caused by them is long-lasting.
In order to eliminate, at least partly, the above problem, a great number of suggestions were made for the domestic annihilation or compacting of such bottles.
The solution is not easy due to the fact that plastic bottles, as opposed to metal containers or boxes, regain a significant part of their volume after stopping of the compression. Thus, compacting can only be performed by using compacting and thermal effect simultaneously, wherein the thermal effect does not allow the bottles to increase their volume after ceasing of the compression, as a consequence of their elasticity. If, namely, bottles are compressed in their melted state, they do not change their form after cooling down.
Known bottle compactors generally comprise a housing or frame receiving the bottle, heating means and compressing means.
EP 0707932 discloses a bottle compactor containing a housing chamber designed to receive an empty bottle. The housing is provided with a resistor and a cursor, the end of which is formed like a fork engaging the plastic bottle at its neck part. The cursor with the fork compresses the heated and softened bottle from the upside down. The cursor can be operated manually by means of a lever.
FR 2694722 describes a portable device, wherein the power for compacting the bottle arranged in a housing having resistance heating is provided by a spring.
In the bottom of the apparatus described in FR 2668732, there is a separate heating chamber wherein air is heated by resistance heating and the heated air is pulsed by a fan into a volume containing the plastic bottle, which is compacted by a plate moved by motor driven spindles.
In all the above devices, the bottles are heated from below, and they are usually compressed from above. As a result, the folded plastic layers are irregular and, in this way, optimal compression can not be achieved.
In other devices, heating is provided along the whole length of the device and/or by means of a patron intruding into the bottle. Such an apparatus is described e.g. in FR 2692190. In this case, the above mentioned disadvantage, namely the irregular compacting is especially obvious and, in addition, the energy consumption increases significantly as well.
In FR 2712230 the disclosed apparatus has a closed housing with a central heater intruding into the bottle which is compressed both from top to bottom and from bottom to top. The disadvantage of this is the unnecessarily increased energy requirement of compression and, further on, it is complicated and expensive.